div{
	box-sizing: border-box;
}
body{
	margin: 0;
	padding: 0;
}
.box1{
	width: 200px;
	height: 200px;
	border:1px solid black;
	background-color: red;
}
.box2{
	width: 200px;
	height: 200px;
	border:1px solid black;
	background-color: green;
}